The summer is flying by despite the lack of sun shine and the tern breeding season here in Langstone Harbour is already half way through. It's been a tough one to be sure but there have been some silver linings and there is still the potential for a lot more. Let me take you though the season so far.
As regular readers of this blog will know, the little tern breeding season didn't start well at all (see previous blog here) with much smaller numbers than usual frequenting the harbour and their first breeding attempt failing very early on. The causes of this have been becoming clearer as time has passed and it now looks certain that a witches brew of combined issues led to this failure.
The main factor appears to be a lack of suitable food locally. Our annual small fish surveys, carried out alongside Langstone Harbour Board, The University of Portsmouth's Institute of Marine Sciences and the Southern Inshore Fisheries and Conservation Authority have been indicating a reduced number of fish suitable for terns within the harbour during the first part of the breeding season. This has been backed up with observations of terns carrying fish being scarcer than usual. As the main driving force for breeding location amongst terns is access to a nearby food source, a reduced supply would perfectly explain a decrease in numbers settling. The investigation of this is still in it's early stages and there will be further surveys later in the year which will hopefully fill in some of the blanks we currently have. Of the fish species effected, sandeels and bass (not usually tern prey I should add) appear to be particularly low in number.
The weather has also not been helpful this year and a small storm surge during spring tides caused the loss of many nests throughout Langstone and particularly Chichester Harbour at the start of June. Likewise, the near omnipresent rain has made staying warm very difficult for young chicks (a problem which effected the breeding Sandwich Terns more severely but I'll cover that in a later blog explaining how they still fledged an amazing 45+ & counting youngsters!).
One very unexpected (but thankfully short term and minor) issue faced this year was the appearance of a hedgehog on one of the breeding islands! We're not sure if it walked across in search of food at low tide or if it found itself washed there unexpectedly but it appeared on camera on June 2nd and disappeared after June 6th! Here's the video which first alerted us to it's presence, I can only tell you I was as astonished as the Black-headed Gull in the background by what I was seeing the first time I viewed this!
Although there's no evidence at all to suggest it predated any tern nests (and I'd expect some), we do know it ate it's way through a clutch of Oystercatcher eggs. The real problem this prickly visitor caused was in deterring the nesting terns from locating in the best (highest) areas of the island. Below is a second video showing it's interaction with a nesting common tern (clearly unhappy with a mammal being so close to its eggs) which had a lucky escape. The last sighting we have of this visitor was on June 6th and despite extensive coverage, we've not seen it since. Perhaps connected, a dead hedgehog was found washed up on the shore a few days later. Nevertheless, it adds another (very surprising) factor to consider before next years breeding season begins.
So, with all the problems these little guys are facing, where are we now? That's the good news. Despite my expectations otherwise, the little terns present re-grouped and started nesting again in mid June. This time, they chose areas above the spring tide line and mostly away from the usual threats such as their larger gull neighbours.
Seven pairs of little terns nested and out of these, 5 managed to hatch chicks before their precious eggs were discovered by natural predators (all eggs are now hatched). All of the chicks are being watched closely on camera and from a distance via telescope and so we will know, good or bad, what their eventual fate is. Fingers crossed.
The final chapter to this story will play out over the next 20 days and I'll be sure to update you towards the end of the month when breeding has finished. From this point on, it really is down to nature but whatever happens, the knowledge that these little guys are contributing to our understanding will go on to help their kin around the country and within the Solent for years to come. I'm routing for them.
As they grow over the next three weeks, in a joint study with Natural England, their diet will be recorded on video and the fish they're being bought by their parents logged. With this knowledge, we should be able to further advance what we know about their food requirements, variation and what other issues they are facing.
Without further ado, here are the plucky little fellas and lasses of 2016, currently striving through the weather to put on weight, grow their feathers and take those first hops into the sky.
Above: First light, these guys are straight out of the egg, less than 24 hours old.
Above: Siblings in exploration mode. These two are 4-5 days and are now able to hide until their parents come back with fish, at which point they jump out and make themselves known!
Above: Resting between feeds, this little guys is 3 days old and like his contemporaries, spends all his time between eating asleep. Given the amazing rate of growth going on (it'll be able to fly in 20 days) I don't blame you little fella.
Finally, here they are in motion :)
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